Our analyses supported the multidimensionality for Version 6 of the Addiction Severity Index (ASI-6) similar to that which had been found in earlier versions of the instrument. The psychometric analyses to derive Recent Status Scores (RSSs) for the ASI-6 yielded nine primary scales, one for each of six areas (i.e., medical, employment/finances, alcohol, drug, legal, psychiatric) and three in the family/social area. Six scales, Medical, Employment, Alcohol, Drug, Family/Social Support and Child Problems, met all initial conditions for a strong quality scale (all Hij
≥ 0.3, α ≥0.70). The remaining three scales approached these values but fell a bit short on one metric (i.e., Legal, miniHi
= .28; Family/Social Problems H
= 0.49; Psychiatric, H
= 0.48) and can conservatively be considered moderate quality scales. As all quantities are measured with some error, and occasionally items were included based on substantive reasons to more fully represent the construct under consideration, it is not surprising that some final scales slightly missed the desired thresholds. The CFA provided additional support for the scales indicating that the items were correctly assigned to the scales, and that the scales measured distinct dimensions. The intercorrelations among the nine RSSs further supported the multidimensionality of the ASI-6, revealing relative independence of the different life functioning areas. The stronger relationships were those that also had been identified with previous versions of the ASI [6
Analyses of the generalizability of the derived scales to males versus females and whites versus blacks generally supported the comparability of the findings with some slight exceptions. The comparison of the item-pair Hij statistics between demographic groups provided some assurance that similar scales would have been selected, if the exploratory analysis had been performed separately on the subgroups. For males versus females there was no significant evidence that the differences in Hij classification were greater than would be found by chance. For blacks versus whites, while the results were statistically significant the magnitude of the difference between them was small. The examination of whether the final scales would have acceptable scalability and reliability if evaluated on each of the four subgroups separately revealed that in most cases, the Legal, Family/Social Problems, Problems with Children, and Psychiatric scales missed the targets in a similar manner when using the entire sample and any discrepancies were well within what might be expected from the smaller sample sizes of the subgroups. Thus, questions do remain regarding generalizability to both the specific subgroups that were subjected to analyses and to other important subgroups. Future analyses on larger samples can provide new and more definitive data concerning the generalizability of the RSSs.
The concurrent validity analyses with the external measures yielded strong evidence supporting the validity of six of the RSSs (Medical, Alcohol, Drug, Employment Family/Social Problems, Psychiatric). The external validity measures for these areas were arguably better than for those in the remaining areas. They assess recent status, are directly related to the corresponding ASI-6 area, and are psychometrically strong scales comprised of multiple items (with the exception of the single SAS-SR employment item). The evidence for concurrent validity was minimal in the Legal area. Possible reasons are that a history of documented prior arrests may be relatively insensitive regarding very recent illegal behavior as measured by the Legal RSS. Similarly, the CPI-So, a personality measure, may be insensitive to specific recent behaviors occurring over only a short period of time. It is encouraging that additional predictive analyses yielded a correlation of 0.34 between the Legal RSS and documented arrest in the two-year period following study intake. Regarding the Family/Social Support and Child Problems RSSs there were admittedly no direct external validity measures. A negative correlation between the ASI-6 measure of support and the global SAS-SR measure of family/social functioning was nonetheless unexpected. One possible explanation is that the Family/Social Support RSS's content consists largely of items that have to do with interpersonal contact. Thus the opportunity for more problems may exist for those respondents with lower scores (i.e., more support) than for those who are more isolated. Future studies that compare this RSS with direct measures of support (e.g., the Social Provisions Scales) [SPS; 55] would be informative and are warranted. There was also no direct external validity measure for the Child Problems RSS. It was not related to the summary score provided by the SAS-SR, likely because this measure is far too general to be sensitive to specific problems assessed by a Child Problems Scale. The uniformly low correlations of the ASI-6 Child Problem RSS with the external measures selected seem to neither support nor challenge its validity. Again, future studies that compare this RSS with direct corresponding measures are warranted.
Seven of the nine RSSs closely parallel the scales that measure recent functioning derived from earlier versions of the ASI (ASI-3/5) (i.e., Medical, Employment, Alcohol, Drug, Legal, Family/Social Problems, Psychiatric), and some content in each ASI-6 scale overlaps with content in the corresponding recent scale(s) from earlier versions. For these seven areas, it is therefore not surprising that the scalability and reliability, intercorrelations among the RSSs, and the concurrent/external validity results for the ASI-6 are roughly comparable to the results obtained with similar analyses using the ASI-3/5. This being said, a natural question is, “Why use the ASI-6 instead?” Specifically, ”What are the advantages of the ASI-6 regarding the assessment of recent functioning?” There are several facets to our response:
First, the set of 118 items analyzed to derive the nine RSSs included the content of the total 165 ASI-6 recent status items. This is in contrast to the content of approximately 80 recent status items used to derive summary scales to measure recent functioning with earlier versions of the ASI (ASI-3/5). Moreover, in nearly all of these seven ASI-6 scales the number of items included exceeded those in the corresponding ASI-3/5 scales. Thus, the ASI-6 offers more comprehensive content in its scales than do those derived with earlier ASIs. Examples of the enhanced content versus earlier ASIs are additional items that query last use and specific types of problems (e.g., craving, withdrawal) in the alcohol and drug areas of the ASI-6. Also, in the psychiatric section the inclusion of items that assess the substance-relatedness for each specific symptom endorsed, the most recent occurrence of the more severe symptoms, days hospitalized for mental health problems, and patient ratings of trauma-related distress and treatment needs are items not included in earlier ASIs. In a related manner, the ASI-5 and ASI-6 recent psychiatric measures performed similarly in identifying co-morbidity, but the ASI-6 performed better for PTSD [56
Second, there are numerous ASI-6 recent status items that are not in the earlier ASIs and have clinical and/or research value (e.g., homelessness, pregnancy, tobacco use, gambling) but did not emerge in the RSSs.
Third, in addition to the seven ASI-6 scales that parallel those found in earlier ASIs, it was possible to delineate two more specific summary measures in the ASI-6's family/social area (i.e., Family/Social Support, and Child Problems) due to its greater differentiation and expansion. In this regard, additional analyses yielded six additional preliminary scales in the family/social area; problems and support with the respondent's spouse/partner, other family, and friends. To varying degrees, these scales approached or exceeded the targets for quality scales, but since the content overlapped completely with the Family/Social Support and Family/Social Problems RSSs we decided that the more global measures would be among the set we consider primary ASI-6 summary scales.
It should be acknowledged that our inability to derive a more comprehensive or several more specific RSSs in the employment/finances area was a disappointment given the ASI-6's expanded coverage. In this regard, one limitation of the current study was that the study sample was not entirely representative of the larger population of SUD patients in this country. The majority of participants were unemployed African Americans treated in largely publicly funded programs. In particular, only a small minority was employed. It is possible that a more comprehensive or additional RSS would have emerged for the Employment/Finances area, if a greater proportion of those assessed had been employed and less financially marginal. Nonetheless, we included patients from multiple treatment organizations and modalities, and the sample may not be dissimilar in important ways from an urban, particularly inner city, U.S. treatment-seeking population.
In addition to the non-representativeness of the study sample, another limitation of the current analysis was the relatively small sample size for such a major undertaking. A larger and more sociodemographically diverse sample would yield more definitive findings, although we would anticipate substantial convergence between the results of the current study and those of a larger study.
In conclusion, our analyses supported the multidimensionality of the ASI-6 that had been found in earlier versions of the instrument (i.e., the relative independence of the important different functional areas) with quality scales that assess recent functioning. These positive findings with the ASI-6 coupled with its updated and more extensive content, and similar administration time compared to earlier ASIs support the use of the ASI-6 in clinical practice and research. Additionally, the current study has provided the foundation for future research in order to further confirm or extend our findings. Translations of the ASI-6 into other languages have been accomplished and such research is ongoing in other countries (e.g., Brazil, Spain) [57
]. Specific future directions we plan to pursue are the derivation of lifetime summary scores, and comparison studies of the ASI-6 and the ASI-5.